In football training, it is necessary for passers, kickers and receivers to repeatedly practice formations, plays and given situations. On any team there are only a relatively few passers and kickers, but a great number of receivers. Hence, passers and kickers get adequate practice in their specialty, but they simply cannot pass and/or kick the ball often enough to give the receivers the desired practice in offensive or defensive pass and kick handling and/or handling of center snaps.
For many years machines have been available that can throw footballs to emulate either spiral or end-over-end flight form. One version of such a machine is disclosed in U.S. Pat. No. 4,026,261 which describes a machine that employs two spaced apart rotatably-driven pneumatic-tired wheels that have their outer surfaces confronting each other and spaced apart a distance less than the maximum diameter of a football to be thrown. Means are provided to allow a football to enter the nip or space between the tires whereupon the ball is pulled into the nip and thrown from the opposite side into a trajectory and in a flight form determined by a number of factors. These factors include the alignment of the ball upon engagement by the wheels; the relative positions of the wheels; and the direction in which the wheels are aimed. The wheels are mounted in such a way that the planes in which they rotate can be independently varied. In this manner, the direction and rate of spin of a spiral pass or punt can be set. Alternatively, the wheels can be positioned to rotate in the same plane as is often done to attain end-over-end flight. In the prior machines, footballs to be thrown are loosely rested on a cradle that is pushed toward the apex of the nip between tires for engagement thereby. The apex of the nip is midway on a line or axis that extends between and is transverse to the centers of the axles of the two wheels and at the centers of the confronting surfaces. The wheels and the planes in which they rotate are adjusted by pivoting about this axis. The entire wheel assembly may be tilted up and down and swung side-to-side to aim the football.
For spiral flight, the ball is pushed toward and into the center of the nip between tires in a path parallel to the long axis of the ball. To achieve end-over-end flight the football is either tilted or the long axis is moved in a path that does not extend through the apex.
From the general standpoint of throwing a football, the above described prior machine does work quite well, but it does have serious drawbacks that prevent its success in hard training. This is so because modern football is a precise game and to attain proficiency it is mandatory that passes, kicks and center snaps often be virtual duplicates and that they be repeated many times. This is simply not possible with prior machines. Thus, a major disadvantage of prior machines is that they cannot precisely repeat throws. That is, even though the setting and speed of the wheels remains constant, successive throws vary significantly in distance, trajectory and direction. This defeats the goal of practice by repetition.
Other disadvantages of prior machines include the lack of a reliable feeder enabling the throwing of a number of footballs without stopping to reload and the inability to quickly change the adjustments of the machine from an operator's station to accomodate different requirements.